Dstream 火花流

Question

你好我写了下面的代码

val receivedStream: DStream[PubsubSparkMessage] =
      PubsubSource.createStream(ssc, pubsubConfig, pubsubSubscriber)
    @volatile var receivedMessages: List[PubsubSparkMessage] = List() //scalastyle:ignore
    receivedStream.foreachRDD { rdd =>
      if (!rdd.isEmpty()) {
        receivedMessages = List(rdd.collect)
        receivedMessages
      }
    }

我收到一个错误，因为类型不匹配； 我的问题是如何将 List[Array[PubsubSparkMessage]] 修改为 List[PubsubSparkMessage]

Answer 1

类似于：

val list : List[Array[PubsubSparkMessage]] = List()

val result = list.flatMap(x => x)